diff options
| author | shigek <shigek@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2003-08-19 14:16:09 +0000 |
|---|---|---|
| committer | shigek <shigek@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2003-08-19 14:16:09 +0000 |
| commit | caf213d9ad1fd277d1cc615306d3eb662c2283af (patch) | |
| tree | 97f4ba2a081bde542b91db9b9d092ad9fea76939 /ext | |
| parent | c41b3b96ab097540bcf66a43639233ce47b8e219 (diff) | |
E added. Typo corrected.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@4411 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Diffstat (limited to 'ext')
| -rw-r--r-- | ext/bigdecimal/lib/bigdecimal/math.rb | 25 |
1 files changed, 22 insertions, 3 deletions
diff --git a/ext/bigdecimal/lib/bigdecimal/math.rb b/ext/bigdecimal/lib/bigdecimal/math.rb index f6a3ff6a62..7b3f46ed1a 100644 --- a/ext/bigdecimal/lib/bigdecimal/math.rb +++ b/ext/bigdecimal/lib/bigdecimal/math.rb @@ -7,6 +7,7 @@ # exp (x, prec) # log (x, prec) # PI (prec) +# E (prec) == exp(1.0,prec) # # where: # x ... BigDecimal number to be computed. @@ -51,7 +52,7 @@ module BigMath end def cos(x, prec) - raise ArgumentError, "Zero or negative precision for sin" if prec <= 0 + raise ArgumentError, "Zero or negative precision for cos" if prec <= 0 return BigDecimal("NaN") if x.infinite? || x.nan? n = prec + BigDecimal.double_fig one = BigDecimal("1") @@ -76,7 +77,7 @@ module BigMath end def atan(x, prec) - raise ArgumentError, "Zero or negative precision for sin" if prec <= 0 + raise ArgumentError, "Zero or negative precision for atan" if prec <= 0 return BigDecimal("NaN") if x.infinite? || x.nan? raise ArgumentError, "x.abs must be less than 1.0" if x.abs>=1 n = prec + BigDecimal.double_fig @@ -96,7 +97,7 @@ module BigMath end def exp(x, prec) - raise ArgumentError, "Zero or negative precision for sin" if prec <= 0 + raise ArgumentError, "Zero or negative precision for exp" if prec <= 0 return BigDecimal("NaN") if x.infinite? || x.nan? n = prec + BigDecimal.double_fig one = BigDecimal("1") @@ -174,4 +175,22 @@ module BigMath end pi end + + def E(prec) + raise ArgumentError, "Zero or negative precision for E" if prec <= 0 + n = prec + BigDecimal.double_fig + one = BigDecimal("1") + y = one + d = y + z = one + i = 0 + while d.nonzero? && ((m = n - (y.exponent - d.exponent).abs) > 0) + m = BigDecimal.double_fig if m < BigDecimal.double_fig + i += 1 + z *= i + d = one.div(z,m) + y += d + end + y + end end |